Brake lights of a vehicle are activated in response to the vehicle operator applying manual force to the vehicle's brake actuator(s), for example, the operator depressing the brake pedal or, for motorcycles, the rider/operator squeezing the hand brake lever or pressing the foot pedal. The brake lights thereby give drivers behind the vehicle immediate, attention capturing notice of the vehicle's friction braking deceleration, and therefore earlier opportunity to adjust their speed, e.g., apply their brakes, to avoid colliding with the operator's vehicle.
However, the brake lights warn drivers behind a vehicle only of brake deceleration; they give no warning to drivers behind a vehicle if it decelerates due to any other cause, e.g., engine braking from the operator reducing the engine throttle, or downshifting the transmission to a lower gear, or both. On the contrary, when a vehicle decelerates for a reason other than the operator applying the brakes, the first “alarm” to a driver behind it is that driver's realization that the distance between the driver's vehicle and the vehicle in front of him is closing rapidly. Unfortunately, due to factors such as vehicle speed and driver distraction, the realization sometimes is too late.
Acceleration sensing devices have been used to detect vehicle deceleration for brake light operation independently of intentional operation of the brake by a driver. However, acceleration measuring devices produce detection outputs in response to accelerations along each of multiple axes. Basing vehicle deceleration directly upon such multi-axial acceleration measurements can result in false indications of deceleration such as may occur when a vehicle, especially a motorcycle, is leaning into a turn or encountering changes in road grade, etc. Such false indication of deceleration, to drivers following the vehicle, can be inconvenient and even dangerous. A solution to these problems is needed.